1. Field of the Invention
The present invention relates to a design support apparatus for performing a design support for an apparatus such as a sheet conveying apparatus, and a design support method therefor.
2. Description of the Related Art
In recent years, accompanying the improvements in computer performance, the switch from two-dimensional CAD to three-dimensional CAD is progressing rapidly with respect to CAD that is used for machine design service. Further, nowadays it has become common to verify the device design using a simulator by utilizing three-dimensional CAD data that is created prior to manufacturing the actual apparatus (actual machine).
In the case of designing an apparatus that conveys a sheet member such as a paper sheet or a film also, there is a demand for verifying the conveyance design for the sheet member (sheet conveyance design) before manufacturing the actual apparatus. Examples of an apparatus that conveys a sheet member such as a paper sheet or a film include a copying machine, a laser beam printer, an inkjet printer, a card printer, and a facsimile device.
When verifying the sheet conveyance design, the machine designer performs modeling of a sheet conveying unit on three-dimensional CAD, defines the principal section, cuts the sheet conveying unit to form a section, and creates a two-dimensional plotting thereof. The machine designer then designs attributes that are required for sheet conveying such as the sheet conveying path, sensors, conveying rollers, conveying guides, sheet guides, and flappers. Thereafter, in order to pass the information to a software designer, the machine designer verifies the conveying speed and the control method in each component section.
Speed enhancement and downsizing is being implemented more and more in recent apparatuses, and it is thus necessary for a large amount of sheets to be quickly conveyed within a narrow apparatus at one time. Verifying a conveying speed or a control method at the time of the concept design in order to satisfy this design specification has become a large burden for machine designers.
Generally, a machine designer graphs (diagrams) the moving distances on a time axis of the leading ends and the trailing ends of sheets to be conveyed, and finalizes the design specifications while checking whether or not a space between sheets is ensured. When this diagram is decided, the machine designer graphs (makes a timing chart for) speed variations in a plurality of rollers or ON/OFF operations on the time axis of a sensor based on that diagram, and finalizes the roller control information. At this time, since the plurality of rollers are not rotationally driven independently, but instead are divided into several groups for each motor and driven, there is a risk that it will not be possible to make the sheets flow in the manner decided in the diagram. Therefore, the machine designer conducts a final check.
A timing chart in which definitions for rollers and sensors and the like are completed, is used as a software design specification sheet and also as a driving chart for checking the operations of the actual machine before the firmware is completed.
Japanese Patent No. 2615757 discloses technology that increases efficiency by systemizing this kind of timing chart (also referred to under another name as “input chart”) as a creation support tool, instead of creating the timing chart by performing a manual operation. More specifically, according to this technology, data for the X and Y coordinates of change points P1, P2, P3, and P4 at which the conveying speed of the leading end of a sheet that is conveyed inside an image output apparatus is graphed to express as sheet status data. Based on this sheet status data, the movements of the trailing end of a sheet and of paper sheets comprising a plurality of sheets are graphed. A timing chart is then created from the resulting graph.
Further, Japanese Laid-Open Patent Publication (Kokai) No. 2000-003292 discloses technology that increases efficiency by systemizing a created timing chart as a verification tool, instead of the designer him or her self printing out a sequence program for creating the timing chart to correct bugs and performing verification by operating the actual machine. More specifically, according to this technology, input contact points of the timing chart are extracted and whether or not desired operations are satisfied is detected by performing a comparison with the sequence program.
With a conventional design support apparatus, when creating a diagram that shows the movement of a sheet, a graph of the sheet trailing end is created by simply subjecting a graph of the sheet leading end to offset duplication with respect to the paper size. Therefore, when actually conveying sheets in a copying machine, it has not been possible to represent on a diagram a graph that shows a state in which, for example, a sheet collides with a stopped roller and the sheet bends to create a loop.
Further, although a start-up curve, a shut-down curve and the like that are referred to as “stabilization constants” exist for each motor, it has not been possible to plot diagrams with a simple calculation that incorporates these factors. In order to determine the X and Y coordinates of change points P1 and P2 on a graph, it has been necessary to calculate the transit time based on the distance and speed each time. Consequently, when the speed of one section is increased it is necessary to recalculate the time taken for a sheet to pass through all the sections, and it has not been possible to change the diagram in question in real time.
Further, when passing through a plurality of sheets, graphs are created on the premise that the graph for the first sheet is duplicated. Thus, when the control method for the second sheet is not the same as for the first, it has not been possible to simply perform additional plotting. Further, after creating a diagram, it has been necessary to create a timing chart while working out linear-function intersecting point formulas one by one, which has required man hours.
For these reasons, since unsatisfactory points remain with respect to the accuracy and plot creation time of the diagram itself, there has been a problem regarding the accuracy and efficiency of a timing chart that is created based on the diagram.
Originally, conventional design support apparatuses have been utilized on the premise that upon finishing a study of a sheet conveying concept, the sheet conveying concept is illustrated in a diagram, and it has not been assumed that the design support apparatuses will be used from the design concept stage. Consequently, design support apparatuses have been unsuitable for repeated study of concepts.
Further, an approach in which a sheet conveyance sequence is studied using only a diagram has been understandable to only designers. Accordingly, it has been difficult for personnel in evaluation and productions departments such as the quality assurance department, the trial manufacture department, and factory departments to immediately understand the manner in which sheets move inside the copying machine main unit. Therefore, at the time of a design review, time has been required for sharing design information.
Furthermore, even when the diagram is completed, since each roller does not operate independently there has been the following problem. Namely, in the case of a common copying machine or printer, a plurality of conveying rollers are rotationally driven at the same time employing a single motor as a power source. Therefore, there are sections in which the speed must be uniform even if the rollers are separate. At the time of diagram creation, diagrams are sometimes plotted in which these kinds of sections are ignored and the speed (inclination) is changed. Consequently, there has been the risk that a mistake will occur in the speed settings with respect to drive division for such rollers.
On the other hand, although Japanese Laid-Open Patent Publication (Kokai) No. 2000-003292 discloses technology that evaluates the correctness of a timing chart as described above, this technology has basically only studied the ON/OFF timing time. The technology has not compared the speed of the ON sections.